Selection in the Making: A Worldwide Survey of Haplotypic Diversity Around a Causative Mutation in Porcine IGF2

A. Ojeda^*, L.-S. Huang, J. Ren, A. Angiolillo, I.-C. Cho, H. Soto^**, C. Lemús-Flores, S. M. Makuza, J. M. Folch^* and M. Pérez-Enciso^*^,^,1

^* Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain, Key Laboratory for Animal Biotechnology of Jiangxi Province and the Ministry of Agriculture of China, Jiangxi Agricultural University, Nanchang 330045, China, Dipartimento di Scienze e Tecnologie per l'Ambiente e il Territorio, Facoltà di Scienze Matematiche, Fisiche e Naturali, Università del Molise, 86090 Pesche, Italy, Division of Livestock, National Institute of Subtropical Agriculture, R.D.A., 175-6, O-Deung Dong, Jeju, 690-150, South Korea, ^** Facultad de Ciencias Agroalimentarias, Universidad de Costa Rica, San Pedro, Costa Rica, Universidad Autónoma de Nayarit, 63155 Tepic, Mexico, Department of Animal Science, University of Zimbabwe, MP167, Mount Pleasant, Harare, Zimbabwe and Institut Català de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain

^¹ Corresponding author: Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
E-mail: miguel.perez{at}uab.es

Domestic species allow us to study dramatic evolutionary changesat an accelerated rate due to the effectiveness of modern breedingtechniques and the availability of breeds that have undergonedistinct selection pressures. We present a worldwide surveyof haplotype variability around a known causative mutation inporcine gene IGF2, which increases lean content. We genotyped34 SNPs spanning 27 kb in 237 domestic pigs and 162 wild boars.Although the selective process had wiped out variability forat least 27 kb in the haplotypes carrying the mutation, therewas no indication of an overall reduction in genetic variabilityof international vs. European local breeds; there was also noevidence of a reduction in variability caused by domestication.The haplotype structure and a plot of Tajima's D against thefrequency of the causative mutation across breeds suggesteda temporal pattern, where each breed corresponded to a differentselective stage. This was observed comparing the haplotype neighbor-joining(NJ) trees of breeds that have undergone increasing selectionpressures for leanness, e.g., European local breeds vs. Pietrain.These results anticipate that comparing current domestic breedswill decisively help to recover the genetic history of domesticationand contemporary selective processes.